harmonics generation

[MHD NA]

Hi all optisystem members,
i am designing the attached osd. The results must be harmonics of signal (1.5 GHZ) on the sixth harmonic of signal (3 GHz).
My results: obtaining the sixth harmonic but the harmonics of (1.5 GHz) didn’t appear….What’s the reason?

Regards,

Attachments:

1. mm3.osd

[MHD NA]

Sorry, I have forgotten to attach my sorry. Here you are..
I am waiting your help ASAP for my Master

Regards,

Attachments:

1. 

   my-results.png
   

[alistu]

Hi Mohammad,

I am not able to get the figure you have obtained in the attached image in your above comment. The figure belongs to “RF Spectrum analyzer” as can be seen from the visualizer screenshot, but I have attached what I get from the same visualizer. Please verify if the settings in your file are the same. Thank you.

Attachments:

1. 

   RfSpect.jpg
   

[MHD NA]

Hi alistu,
you have all right and your attached photo is for stage before last LPF. Wherease my photo is for stage after LPF and after amplifiction.
As you Know you can change the measured range to become (10-20) GHz at the end of optical line, so you can obtain my attached photo.
please, Try what i said and give me your opinion.

with Regards,

[MHD NA]

and here you are my results after photo-detector which show they are compatible with your results in your attached photo, but my problem is: no presence for harmonics of (1.5 GHz) at the end of line….that is my problem

Regards,

Attachments:

1. 

   after-PD.png
   

[alistu]

I think the problem comes from the fact that you have chosen a Bandpass filter, and not a “low pass filter”, contrary to what you have mentioned in your reply #25834. The filter is centered at 18GHz with a bandwidth of 2GHz. Please see the output signal from PIN, in which a harmony is seen at 1.5GHz (Otherwise, I don’t know why you have mentioned “LPF” in your comment).

Regards

Attachments:

1. 

   harmony1.5.jpg
   

[MHD NA]

Hi alistu,
1- I chose BPF to select only the sixth harmony of 3 GHz which is 18 GHz (i achieved that).
2- The harmonics of 1.5 GHz form double sides (DSB) on each harmony of 3 GHz.
3- so I chose LPF to select lower side of harmonics 1.5 GHz on the 18 GHZ.
N.B. I chose 18 GHz to perform local carrier which carry the harmonics of 1.5 GHz.

Regards,

[Author]

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